Does anyone know why the rear brake pistons must be turned while compressing back into caliper and not the front?I,ve never heard of it previous to owning a mini.

 

Because inside of the piston is a worm screw that is used to apply pressure to the pads when you pull the parking brake. Over time as the pads wear the piston must move and stay out more for this to work. As you yank on the handle and or apply pressure to the caliper this rotates the piston out to keep this distance in check. When you retract the piston back in you are simply winding it back up the shaft to start all over again.

 

Thanks for the fast answer.